Abstinence from sex until marriage and faithfulness after marriage is frequently promoted as a means of preventing HIV transmission, and if both partners are both abstinent and faithful, it will be effective. However, abstaining from sex until marriage is often the exception rather than the rule, and a partner who abstained can contract HIV from one who did not. Honest communication is critical. In many cultures, discussing sex is taboo, which contributes to HIV transmission. Changing cultures requires cultural sensitivity. Educating people about HIV itself and letting them develop culturally specific responses may be most effective.